Cache.h

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/*
// $Id: //open/dev/fennel/cache/Cache.h#20 $
// Fennel is a library of data storage and processing components.
// Copyright (C) 2005-2009 The Eigenbase Project
// Copyright (C) 2005-2009 SQLstream, Inc.
// Copyright (C) 2005-2009 LucidEra, Inc.
// Portions Copyright (C) 1999-2009 John V. Sichi
//
// This program is free software; you can redistribute it and/or modify it
// under the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 of the License, or (at your option)
// any later version approved by The Eigenbase Project.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/

#ifndef Fennel_Cache_Included
#define Fennel_Cache_Included

#include "fennel/common/ClosableObject.h"
#include "fennel/device/DeviceAccessScheduler.h"
#include "fennel/cache/CacheAccessor.h"
#include "fennel/common/StatsSource.h"

#include <boost/enable_shared_from_this.hpp>

FENNEL_BEGIN_NAMESPACE

class CacheParams;
class PagePredicate;
class CacheAllocator;
class CacheStats;

class FENNEL_CACHE_EXPORT Cache
    : public ClosableObject,
        public CacheAccessor, public StatsSource,
        public boost::enable_shared_from_this<Cache>
{
    friend class CachePage;

protected:
    uint cbPage;

public:
    static const DeviceId NULL_DEVICE_ID;

    static SharedCache newCache(
        CacheParams const &cacheParams,
        CacheAllocator *bufferAllocator = NULL);

    virtual ~Cache();

    virtual void setAllocatedPageCount(uint nMemPages) = 0;

    virtual uint getMaxAllocatedPageCount() = 0;

    virtual uint getAllocatedPageCount() = 0;

    virtual void collectStats(CacheStats &stats) = 0;

// ----------------------------------------------------------------------
// Accessor Methods
// ----------------------------------------------------------------------

    uint getPageSize() const
    {
        return cbPage;
    }

    virtual CacheAllocator &getAllocator() const = 0;

// ----------------------------------------------------------------------
// Device Registration and Operations
// ----------------------------------------------------------------------

    virtual void registerDevice(
        DeviceId deviceId,SharedRandomAccessDevice pDevice) = 0;

    virtual void unregisterDevice(
        DeviceId deviceId) = 0;

    virtual SharedRandomAccessDevice &getDevice(DeviceId deviceId) = 0;

// ----------------------------------------------------------------------
// Global Operations on Pages; also see CacheAccessor methods
// ----------------------------------------------------------------------

    virtual uint checkpointPages(
        PagePredicate &pagePredicate,
        CheckpointType checkpointType = CHECKPOINT_FLUSH_ALL) = 0;

    virtual bool isPageMapped(BlockId blockId) = 0;

    virtual CachePage &lockScratchPage(BlockNum blockNum = 0) = 0;

    virtual DeviceAccessScheduler &getDeviceAccessScheduler(
        RandomAccessDevice &) = 0;

    // partial implementation of CacheAccessor
    virtual SharedCache getCache();
    virtual uint getMaxLockedPages();
    virtual void setMaxLockedPages(uint nPages);
    virtual void setTxnId(TxnId txnId); // ignored
    virtual TxnId getTxnId() const;

    // implementation of StatsSource
    virtual void writeStats(StatsTarget &target);

private:
    // notification methods called from friend Page
    virtual void notifyTransferCompletion(CachePage &,bool bSuccess) = 0;
    virtual void markPageDirty(CachePage &) = 0;
};

FENNEL_END_NAMESPACE

#endif

// End Cache.h

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